The Chinese commenced road-building long before the Christian era. They graded the roadway and then covered the whole with hewn blocks of stone, carefully jointed and cemented together so that the entire surface presented a perfectly smooth plane. Such roads, although very costly to build, are almost indestructible by time. In China, as well as in several other countries of Asia, the executive power has always charged itself with both the construction and maintenance of roads and navigable canals. In the instructions which are given to the governors of the various provinces these objects, it is said, are constantly commanded to them, and the judgment which the court forms of the conduct of each is very much regulated by the attention which he appears to have paid to this part of his instructions. This solicitude of the sovereign for the internal thoroughfares is easily accounted for when it is considered that his revenue arises almost entirely from a land-tax, or rent, which rises and falls with the increase and decrease of the annual produce of the land. The greatest interest of the sovereign, his revenue, is therefore directly connected with the cultivation of the land, with the extent of its produce and its value. But in order to render that produce as great and as valuable as possible, it is necessary to procure for it as extensive a market as possible, and, consequently, to establish the freest, the easiest and the least expensive communication between all the different parts of the country, which can be done only by means of the best roads and the best navigable canals.